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anthonymcgrath

FEM with alembic animation cache

hey everyone - can anyone help me with this please?  I've watched numerous tutorials on FEM online and i've gone through numerous threads on here but i'm simply having no luck.
I'm trying to get an animated character i've exported from maya into houdini and attach a FEM solution to it.  Using the follow target constraint i can attach the FEM mesh to the animated one but no matter what i try and do i just end up with a mesh either falling to the floor or (as in my attached scene) just 'hanging' off the static mesh.

I'm really lost here i've been banging my head at the wall for 2 weeks trying to suss this out.  I've followed scene files by half a dozen guys off vimeo with scene files attached but nobody seems to have a scene file i can look at that involves an animated alembic cache.

Can anyone take a look at my scene please and help me with where i've gone wrong?

thanks
anthony

hou_alembic_char_FEM_flesh_v02.zip

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SUCCESS!!!! I GOT IT WORKING !!! big_smile.png OH MY LIFE I'M SO HAPPY HAHA!

basically i was trying to drive the solid object via the high resolution mesh but the two geometries are radically different so my tet mesh (of 700 points) was just shooting up into the head area (the first 700 points in the hi res mesh!)

so i setup this…

first geometry node - CHAR_STATIC

the alembic piped through a solid embed node, then a group set on that - in my case the group was just the points of the head, body and legs - i wanted the arms to trail and drag behind. i called the group “jiggle”


second geometry node - CHAR_ANIM

similar to the first one with a solid embed. However as i scrub through the mesh kept changing topology. So i stuck a timeshift on it. I then created a pointDeform node and deformed this “frozen” mesh by the original alembic higher up in the network.

the above gave me two tetrahedralized meshes - one static & one animated but holding its tetrahedralized form.


AutoDopnetwork

now i can create the organic tissue as normal. Using the target geometry to deform it. I then created the targetConstraint node and pointed:

constrained object –> CHAR_STATIC

constrained points –> jiggle


as a noob i dont know if this is the best way to do it but it seems like i can plug any alembic mesh of a character in now and get a floppy armed goober dancing about haha

 

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well i tried animating the jiggle group node so that the char is fully constrained then a sphere scales down resulting in his limbs and torso/head becoming floppy but it doesn't seem to want to work weirdly hmmmm

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Hey Anthony,

I am having a similar problem. Might   you have a snapshot of the network so I can see? i would greatly apprecaite it. And my client is looking to see some results. :(

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6 hours ago, dreamagrery2 said:

Hey Anthony,

I am having a similar problem. Might   you have a snapshot of the network so I can see? i would greatly apprecaite it. And my client is looking to see some results. :(

I'll post up some pics and a basic scene file. Do you have some pics or can you describe what you want to do more closely? I've found a few tricks since this post you see

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Hi Anthony,

Glorious. That would be great. Basically, I am trying to have a moving mesh (alembic, obj or bgeo sequence) attached to its respective object. I want to add secondary motion onto my object. But my object is already moving. How do I combine this motion. Greatly appreciate the help.

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Make sure you have a twiddle thru this video too btw.

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